The objectives of this project are to elucidate the molecular mechanisms by which hormones such as insulin, growth hormone, glucocorticoids, thyroxine and catecholamines affect the metabolism of white fat cells. Some work is also being done on the effects of insulin and glucagon on the metabolism of liver cell suspensions. Special interest is placed on the following aspects: The nature of the trypsin-sensitive receptor involved in the interaction of insulin with the plasma membrane of fat cells. The relationship between the effects of insulin on cyclic AMP accumulation and its anti-lipolytic action. The mechanisms by which thyroid hormones increase the accumulation of cyclic AMP in fat cells. The possible involvement of growth hormone and glucocorticoids in the synthesis of protein factors affecting adenyl cyclase activity via DNA-dependent RNA synthesis.